The parotid glands are the biggest salivary glands, and a parotid adenoma is a tumor which may develop inside one of them. Most often, a growth in a parotid gland will turn out to be what is called a benign tumor, meaning it is not cancerous, and parotid adenomas are no exception, being typically benign. The most commonly occurring parotid tumor is an adenoma known as a benign pleomorphic adenoma and, while other kinds of adenomas may develop, they are rare. Benign pleomorphic adenomas are sometimes known as benign mixed tumors. They consist of an outer capsule which encloses epithelial tissue, their growth is slow and they are usually successfully cured by surgical removal.
Symptoms associated with a parotid adenoma may vary, according to where in the gland the tumor is located. Most frequently, the tumor grows very slowly, perhaps over a number of years, and is not painful. Often, a parotid adenoma may be discovered in the form of a lump seen on the face, perhaps while a person is washing. Sometimes, growths can form a lump which may be felt inside the mouth or throat. Very rarely, the facial nerve can be damaged by the tumor, leading to paralysis of part of the face, but this tends to happen more often in association with cancerous growths.
The treatment of a parotid adenoma involves surgery to remove the tumor and part of the parotid gland, while carefully avoiding damage to the facial nerve. As the facial nerve divides inside the parotid gland, its main branches are of glandular origin and could potentially be severed during an operation. Possible health complications might then include loss of facial muscle movement, tear and saliva secretion, and some taste sensation. Even though parotid adenomas are usually benign, in less than 10 percent of cases a tumor which has been left untreated for a long time can change to become malignant, or cancerous. This means that surgical removal is a better option than leaving a tumor in place.
Occasionally, a parotid adenoma will recur following surgery. This is more likely to happen in cases where the growth did not have a full capsule around it, or where the tumor had grown beyond its capsule. Rarely, tumors may burst while an operation is in progress, so that tumor cells are spread around the original location, and this can also increase the chance of recurrence. Fortunately, surgery is usually performed successfully, and the outlook for someone with a parotid adenoma is typically positive.